Or, for Claude Mythos 5.1, which offers the same capabilities to verified organizations: changedmodels/fable-5-1/migration-guide
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12 **Automate your migration with the Claude API skill.** In Claude Code, run `/claude-api migrate` to invoke the bundled [Claude API skill](https://platform.claude.com/docs/en/agents-and-tools/agent-skills/claude-api-skill#migrating-to-a-newer-claude-model). It works for any current Claude model as the target:
12 **Automate your migration with the [Claude API skill](https://platform.claude.com/docs/en/agents-and-tools/agent-skills/claude-api-skill#migrating-to-a-newer-claude-model).** It comes bundled with Claude Code and works for any current Claude model as the target:
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1414 Let Claude Code migrate your code for you
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963963 ```bash CLI
964964 ant beta:messages create \
965 --beta thinking-binding-controls-2026-08-01 \
966 --transform '{content.#(type=="text")#.text,input_transformations}' \
967 --format yaml <<'YAML'
965 --beta thinking-binding-controls-2026-08-01 <<'YAML'
968966 model: claude-fable-5-1
969967 max_tokens: 16000
970968 thinking:
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12551253 ```bash CLI
12561254 ant beta:messages create \
1257 --beta mid-conversation-output-config-2026-07-01 \
1258 --transform 'content.#(type=="text").text' \
1259 --raw-output <<'YAML'
1255 --beta mid-conversation-output-config-2026-07-01 <<'YAML'
12601256 model: claude-fable-5-1
12611257 max_tokens: 4096
12621258 output_config:
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